Optical second-harmonic generation in ferroelectric nanowires

Optical second-harmonic generation in ferroelectric nanowires of potassium dihydrogen phosphate (KDP) and sodium nitrite embedded into chrysotile-asbestos nanotubes from a melt or solution has been studied. The second-harmonic radiation appears to be polarized, and its intensity is unexpectedly high in comparison with bulk materials. Analysis of the polarization characteristics of the observed signal reveals the possibility of the formation of ferroelectric nanocrystals having the same orientation along the matrix nanotubes and randomly orientated in the plane perpendicular to this direction.